This invention relates to a wireless communication system that detects the position of a terminal using a radio signal, and particularly to the setting of the position of a base station.
A method of detecting the position of wireless terminals in a cellular telephone system is suggested which calculates time differences between receptions of signals transmitted from base stations at known positions to a wireless terminal (signal propagation time differences from the base stations to the wireless terminal: T1−T2 and T3−T2) and multiplies the propagation time differences by the velocity of light to obtain differences between signal propagation distances from the wireless terminal to the base stations, i.e. D1−D2=c(T1−T2) and D3−D2=c(T3−T2), so as to detect the position of the wireless terminal (e.g., see JP 07-181242 A).
Also, a method of detecting the position of terminals in a wireless LAN system is suggested which calculates time differences between receptions of a signal transmitted from a terminal to base stations at known positions (reception time differences between base stations: Ti−T1) and multiplies the reception time differences by the velocity of light to obtain signal propagation distance differences from the terminal to the base stations: {|P−Pi|−|P−P1|}=c(Ti−T1), i=2, . . . , n, so as to detect the position of the terminal (e.g., see Atsushi Ogino et al., “Wireless LAN Integrated Access System (1) Study on Position Detecting System”, Proceedings of the 2003 IEICE General Conference, B-5-203, p. 662 (IEICE: The Institute of Electronics, Information and Communication Engineers).